This invention employs the application of graphite to the outer layer only of such a resistive ribbon. U.S. Pat. No. 4,253,775 to Crooks et al discloses a thermal transfer medium in which the resistive layer is a resin and graphite. The graphite is a particular conductive material dispersed throughout the resin. The graphite is suspended in Kapton (trademark of E. I. DuPont de Nemours & Co.), a polyimide resin, and accordingly functions as the conductive material within the resistive layer to achieve resistivity in a range at which heating can occur.
An article entitled "Conductive Materials in a Resistive Ribbon" in IBM Technical Disclosure Bulletin, Vol. 24, No. 4 (September 1981), page 1918 by L. S. Chang et al discloses the manufacture of a resistive ribbon in which the resistive layer is a mixture of carbon and graphite so as to achieve lower viscosity during the processing stages.
Graphite is a well known solid lubricant. Accordingly, it is believed that graphite has been used as an outer lubricant film in various moving systems, including magnetic tape transport systems. In such systems, of course, application of electric current to achieve a degree of heating sufficient for a thermal printing would not be a factor.